Nibbling machines



NIBBLING MACHINES Filed May l2, 1964 4 Sheets-Sheet 1 a :i F/G'. 5

March 23, 1965 E. HER@ 3,174,376

NIBBLING MACHINES Filed May 12, 1964 4 Sheets-Sheet 2 2 E f! i Hf@ a @l E --Qf a L 5 ML-- l |240 9 l @6.2 M 5 f f5 l!" f3 |24 I1 a |l 1 fa i l l Y! f t l a N. l l1 1` i i I1 |I i 5a, y H I "Il l March 23, 1965 E. HERB 3,174,376

NIBBLING MACHINES /IIIIIIIIIIII INVENTOR E. j L n Hel- BY March 23, 1965 Filed May l2, 1964 E. HERB NIBBLING MACHINES 4 Sheets-Sheet 4 INVENTOR aie/7 Hel- BY /W/'ccf J ATTORNEY United States Patent 3,174,376 NIBBMNG MACHINES Eugen Herb, Ditzingen, Kreis Leonberg, Germany, assigner to Messrs. Trumpf & Co., Stuttgart-Weil im Dorf, Germany Filed May 12, 1964, Ser. No. 372,134 Claims priority, application Germany, Jan. 23, li,

1s claims. (3cr. 83.-.395),

The present invention relates to improvements in nibbling machines for punching slots into Work sheets or plates of metal or the like by means of a cutting punch an-d a die in a step-by-step operation in which the feeding movement of the work sheet to` be cut is limited at each cutting stroke by a stop pin.

The present application is a continuation-in-part application of the copending application Serial No. 84,342 tiled January 23,1961.

In nibbling machines of the conventional type, the nibbling punch is provided at the side opposite to the cutting edge with a projection, the front edge of which serves as a stop member to limit the extent of each feeding'movement of the work 'sheet or plate to be cut, while the rear side thereof is supported on the die and thus serves for guiding the punch. During this nibbling operation, very strong lateral forces are exerted upon the cutting side of the punch which are taken up by the projection and the die. The contact pressure between the projection and the die results, however, in very strong friction through which, due to the continuous rapid reciprocating movement of the punch, the tools are heated to high temperature and worn considerably so that the life of the tools is unduly reduced. Since such guiding projections are interfering with the proper formation and the passage of the chips, additional pressures and bending forces are exerted on the punch. ri`hese forces increase with the thickness of the work sheet to be cut, and it is therefore only p ossible to utilize the known nibbling machines for cutting work sheets of limited thickness. When nibbling thick plates, the height of the chips may be reduced to twothirdsof the thickness of the plate and-the materialV cut from the plate will flow to a considerable extent in the direction of its width. The lateral force so exerted on the punch may become so great as to result in breaking of the punch or of the guiding projection thereof.

It is an object of the present invention to provide a nibbling machine which overcomes the above-mentioned disadvantages of nibbling machines according to the prior art.

It is an additional object of the present invention to provide for a nibbling machine which facilitates the shearing of the chips, which will reduce the heating of the punch and the wear thereon, so as to` increase the output of the machine, and permit the nibbling of work sheets or plates of greater thickness than those which could be cut with nibbling machines of known type.`

It is an additional object of the nibbling machine, according to the present invention to permit punching of a starting hole in the work sheet if a slot has to be cut there through which is located in its entirety within the outer periphery of the work sheet.

it is a further object of the present invent-ion to Vprovide a nibbling machine which is composed of only a few and simple parts, so that the machine may be manufactured at reasonable cost and will stan-d up under extended use.

These objects may be obtained according to the present invention by providing the punch with a longitudinal bore through which a stop pin passes withoutbeing affected by the actual working strokes of the punch, and by displaceablysecuring the stop pin to the frame of the-ma- Mice chine, so that when it is moved to an upper position, its lower end surface will be disposed above the worksheet, while when it is moved-to a lower working position, its lower end surface will be disposed slightiy below the upper surface of the work sheet. The stop pin, therefore, passes intothe work sheet to be cutonly to the extent which is required to properly limit the feeding movement of the work sheet. The chips are then free to expand transversely and may move downwardly without exerting any lateral `forces upon the punch. This has the advantage that the nibbling output of the machine as well as the life of the tools will be considerably increased and such a nibbling machine can be used for work sheets of greater thickness than could be cut by previous machines of this kind.

The machine of the present invention preferably includes also means connected to the ram for adjusting the position of the ram between an upper reciprocating position in which the punch carried by the ram, during reciprocation of the latter, stays above a work sheet fed between punch and die, and a lower reciprocating position in which the punch will move during its down stroke with the lower cutting end thereofthrough the work sheet and beyond the top surface of the die, and spring means operatively connected to the stop pin, which spring means are biased to yieldably holdthe stop. pin in an upper rest position in which the lower end o-f the pin isV disposed above the work sheet. The arrangement is made such that the stop pin is moved during adjustment ofthe ram from its upper to its lower reciprocating position from an upper rest position thereof to a lower working position in which the lower end of the stop pin is disposed slightly below the upper surface ofthe work sheet.

The nibbling machine of the present invention further includes releasable locking means for locking the stop pin in its lower working position and means for releasing the locking means when the ram is moved from the lower to the upper reciprocating position thereof, whereby the spring means will return the stop pin to the rest position after the-locking means has been released.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a partly sectioned front view of part of the nibbling machine of the present invention;

FIG. 2 is a partly sectioned side view of the arrangement shown in FIG. l;

FIG. 3 is a cross section taken along line III-III of FIG. 2; Y

FIGS. 4, 4a, 4b and 5 show part of the arrangement shown in FIG. l in different positions of punch and stop pin relative to the die and the work sheet; and Y FIG. 6 is a sectioned front view similar to FIG.` 1, but

drawn to a smaller scale, and showing also an upper part of the machine for adjusting the position lof the ram.

The nibbling machine, according to the present invention comprises a frame or support means 1, in the upper part of which the ram 2 is guided for reciprocating movement in direction of its elongation. A punch 3 is removably secured to ram 2 in the usual manner to permit exchange of the punch. The lower part of frame 1 supports a die 4 which is likewise removably secured to the machine frame to permit its exchange. In the FIGS. l and 2, punch 3 is illustrated in a position in which ,it has just completed its downward stroke and has cut a sickleshaped piece out of a relatively thick work sheet 5.

Punch 3 has a tubular shape, and its longitudinal bore 3a slidably guides a stop pin 6 which is secured to frame 1 of the machine so as to be independent of the working stroke of the punch 3. Stop pin 6 is displaceable between an upper rest position in which its lower end surface 6a is disposed above the work sheet 5, as shown in FIG. 4, and a lower position, as shown in FIG. 5, in which its lower end surface 6a is disposed slightly below the upper surface 5a of the work sheet or plate 5.

The stop pin 6 is provided at its upper end with a screw thread screwed into a threaded bore of a transverse member 8 to permit the lower end surface 6a of pin 6 to be adjusted to different levels corresponding to the thickness of plate 5 so that, when plate 5 is fed in direction of arrow 7 it will engage with and be securely stopped by pin 6. In order to facilitate the adjustment of stop pin 6, the same may be provided with gripping surfaces 6b on which a wrench, or a similar tool, may be applied for turning pin 6 about its axis. For locking the stop pin 6 in its adjusted position, a clamping member 9 in a bore 10 in member 8 may be pressed against stop pin 6 by means or a pin 11 and setscrew 12 (FIG. 2).

The transverse member 8 passes through a longitudinal slot 13 formed in ram 2 so that the latter may carry out its working stroke, While the member 8 may remain in a fixed position. The ends of member 8 are mounted in a pair of plungers 14, each of which is slidable against the action of a compression coil spring 16 along a bore in a guide member 1a of the machine frame. When the stop pin 6 is in its lower working or stopping position, as shown in FIG. 1, each plunger 14 engages a stop member 17. This stop member is indicated in FIG. 2 in dot-and-dash lines, since it is disposed in front of the central plane through which this section is taken, while in FIG. 1 it is shown in dotted lines to indicate that it lies behind the central plane. As illustrated in FIG. 3, cach stop member 17 forms one end of a bolt 18 which is slidably guided within a housing 19, which in turn is connected to the frame 1. Each bolt 18 is acted upon by a compression spring 20 and thereby pressed into a locking position, as shown in FIG. 3, in which each stop member 17 projects beyond the peripheral edge of plunger 14 and maintains the latter in its lower position against the action of spring 16.

The outer ends 18a of bolt 1S are connected to each other by a transverse bar 21 which carries a handle or knob 22 by means of which bolts 18 may be manually retracted. The transverse bar 21 is further provided with a contact pin 23 which is disposed above an inclined cam surface 24a of a cam member 24 secured to the ram 2 by means of a bolt 25.

The machine of the present invention preferably includes also means connected to the ram 2 for adjusting the position of the latter between an upper reciprocating position in which the punch 6 carried by the ram 2 will, during reciprocation of the latter, stay above the upper surface of 5a of a work sheet 5 fed between the punch and the die, and a lower reciprocating position in which the punch 3 will cut with a lower cutting end thereof through the work sheet and move beyond the top surface of the die 4. The means for adjusting the position of the ram are illustrated in FIG. 6.

As can be seen from FIG. 6, the upper portion 2 of the ram is guided for reciprocation in longitudinal direction in a bore of an upper part of the machine frame or support means 1. A drive shaft having an axis normal to the axis of the ram is mounted turnably about its axis in roller bearings 31 and 32 in the machine frame 1 above the upper end of the ram. The drive shaft 30 has an eccentric portion 3a having an eccentricity e1 relative to the shaft axis, and an end portion 30h extending to the right side, as viewed in FIG. 6, from the eccentric portion 30a. The end portion of 30b is supported in a roller bearing 37 carried by a cylindrical member 36, which in turn is mounted in the machine frame turnable about the shaft axis. An eccentric sleeve 33 having an eccentricity e2 surrounds the eccentric portion 30a of the shaft. The

sleeve 33 has an inner surface slidingly engaging the outer surface of the eccentric portion 30a. A pin member 35 is mounted in a bore extending parallel to the shaft axis through the eccentric sleeve 33 and projecting with a free end thereof to one side of the sleeve into a groove formed in the side of the cylindrical member 36 facing the eccentric sleeve and extending substantially normal to the shaft axis. A worm 40 is turnably mounted in the frame 1 beneath the cylindrical member 36 and the worm engages with corresponding gear teeth 41 formed in the peripheral surface of the cylindrical member 36 so that by turning the worm 40 about its axis the cylindrical member 36 will be turned about the shaft axis. A handle or other means, not shown in the drawing, may be fastened to an end of the worm 40 projecting beyond frame 1 for turning the Worm 40 about its axis. Connecting means are provided for connecting the eccentric sleeve 33 to the upper end of the ram 2. These connecting means include an outer sleeve 34 surrounding the eccentric ysleeve 33 and having a projecting portion 34 projecting between the bifurcated upper end of the upper portion 2 of the ram and being swingably connected thereto by a pin 39. A ywheel 42 is connected by means of a key to the left end, as viewed in FIG. 6 of the drive shaft 30, and the flywheel 42 is formed with a groove 42 for engagement with a V-belt, not shown in the drawing, for driving the flywheel and the drive shaft from a motor, likewise not shown in the drawing.

The nibbling machine above described will operate as follows:

Before start of the nibbling operation the worm 40 is turned about its axis to turn thereby the cylindrical member 36 in a direction so that the eccentric sleeve 33 is turned, due to the engagement of the end portion of the pin 35 in the slot 38, to raise the ram 2 to an upper reciprocating position in which the punch 3 carried by the ram will, during reciprocation of the latter, stay above a work sheet 5 fed ybetween the punch 3 and the die 4. The lowest position which the punch 3 will have during reciprocating of the ram 2 in its upper reciprocating position is shown in FIG. 4, that is, the lower cutting edge of punch 3 will always remain above the upper face 5a of the work sheet 5. When the ram 2 has been moved to its upper reciprocating position, the cam face 24a of the cam 24 carried by the ram 2 will engage the free end of the pin 23 and move thereby the bar 21 towards the left, as viewed in FIG. 1, to retract the locking bolts 18 against the force of the springs 20. The transverse member 8 to which the stop pin 6 is fixed is thereby freed and the transverse member 8 with the stop pin 6 carried thereby will move under the influence of the coil springs 16 in plungers 14 upwardly until the plungers 14 engage with upper faces thereof with end faces in the bores 15 of the guide members 1a. The stop pin 6 is thus held in an upper rest position in which its lower end surface 6a is spaced further from the upper surface 5a of the work sheet than the lower cutting end of the punch 3. It should be noted that when the ram 2 is in its upper reciprocating position, the upper transverse face of the slot 13 in the ram will always remain spaced from the upper surface of the transverse member 8 so that the stop pin 6 will stay in its rest position, as shown in FIG. 4 during reciprocation of the ram 2 in its upper position. The work sheet 5 is then placed between the lower end of the punch 3 and the die 4 in a position as shown in FIG. 4.

The position of the ram 2 is then gradually adjusted by turning the worm 40 in a direction opposite to the direction above-mentioned so that the ram 2 is gradually lowered so that the punch 3 will engage, during the reciprocating movement of ram and punch, that is, during the downstroke of ram and punch, the work sheet 5 and partly penetrate thereinto as shown in FIG. 4a to push the material of the work sheet 5 above the opening in the die 4 into the latter. During the beginning of this downward adjustment of the ram 2, the stop pin 6 will stay in its upper rest position as shown in FIG. 4a. During the gradual downward ladjustment of the ram 2 from its upper to its lower reciprocating position, the ram and the punch 3 carried thereby may carry out several working strokes to gradually push the material above the opening of the die 4 downwards to thus punch a starting hole, indicated by the dotted line 5b in FIG. 4, through the work sheet, until finally, when the ram and punch are adjusted to their lower reciprocating position a plug is punched out of the work sheet during the downward stroke of the punch 3 as shown in FIG. 4b. When the ram 2 is adjusted to its lower reciprocating position, the upper transverse face of the slot 13 for-med in the ram will engage, during the downward stroke of the ram, the upper surface of the transverse member 8 and move thereby the transverse member 8 and the stop pin 6 carried thereby, downwardly against the force of the coil springs i6 from the position shown in FIG. 4a to the position shown in Fi'G. 4b in which the lower end surface 6a of the stop pin 6 is located slightly below the top surface 5a of the work sheet 5. At the same time, the cam surface 24a of the cam 24 carried by the ram 2 moves away from the end of the pin member 23 carried by the bar 21, and the locking bolts 18 connected to the bar 21 lare free to move under the influence of the springs 20 from their retracted position to the locking position thereof, in which the ends 17 of the bolts 1S will engage the upper surfaces of theplungers 14 to thus hold the transverse member 8 and the stop pin 6 carried thereby in its working position in which the lower end 6a of the stop pin 6 is slightly below the top surface 5a of the work sheet S.

The position of the cam 2d and the position of the pin 23 are adjusted in such a manner that during recip-rocation of the ram 2 in its lower reciprocating position, the cam face 24a will not engage with the free end of the pin 23 so that during reciproca-tion of the ram 'in its lower reciprocating position, in which the punch will move between the positions shown in FIGS. 1 and 5, the stop pin 6 will always remain in the position as shown in FlGS. l and 5. The work sheet 5 may be fed by hand or by rnechanical means well known in the art and not forming part of the present invention in the direction of the arrow 7 shown in FIG. 5 and its feed movement is stopped by engagement of the stop pin with the surface 5c of the slot punched in the work sheet during the reciprocation of the punch 3. During such reciprocation the punch will cut substantially crescent shaped chips out of the worlf sheet to thus cut a slot into the latter.

After the desired `slot has been cut in the work sheet the ram is again adjusted to its upper position by turning the worm in the proper direction and during such adjustment of the ram to its upper position the cam face 24a will engage the free end of the pin 23 to move the locking bolts 18 towards the left, `as viewed in FIG. 1, thereby freeing the transverse member 8 so that the latter and the stop pin 6 carried thereby will be moved from its lower working to its upper `rest position by the action of the compression springs 16. The handle 22 connected to the bar 21 may also be used to manually move the locking bolts 18 from their locking to their retracted position.

It will -be understood that each of the elements described above, or two or more together, may also find a useful application in other types of nibbling machines diftering from the types described above.

While the invention has been illustrated and described as embodied in a ni-bblingV machine having a stop pin displaceably mounted in a bore of the punch of the machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way yfrom the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for vari# ous applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic orV specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. In a nibbling machine for progressively punching slots in a work sheet, in combination; support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die; a punch carried bysaid ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stayabove a work sheetffed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidablymounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable inlongitudinal direction of said bore; yieldable means carried byY said support means and engaging said carrier means for holding the latter and the' stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier means during reciprocation of said ram in said lower position for moving said carrier means and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; and releasable locking means carried by said support means for releasably holding said carrier means and the stop pin carried thereby in said working position.V Y

2. In a nibbling machine for progressively punching slots in. a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement towardi and away from said die; a punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable in longitudinal direction of said bore; yieldable means carried by said support means and engaging said carrier means for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier means during reciprocation of said ram inV said lower position for moving said carrier means and the stop pin carried thereby against the force of said yield-A able means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means car@ ried by said support means for releasably holding said carrier means and the stop pin carried thereby in said working position; and means operatively connected to said releasable locking means for releasing the same so that said carrier means and said stop pin will be moved by said yieldable means from said working to said rest position.

3. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a

die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die; a punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the ytop surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable in longitudinal direction of said bore; yieldable means carried by said support means and engaging said carrier means for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier means during reciprocation of said ram in said lower position for moving said carrier means and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably holding said carrier means and the stop pin carried thereby in said working position; and means mounted on said ram and engaging said locking means during reciprocation of said ram in said upper position for releasing said locking means so that said carrier means and said stop pin will be moved by said yieldable means from said working to said rest position.

4. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die, said ram being formed with a longitudinal slot extending in direction of movement thereof; a punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; a carrier member extending transversely through said slot in said ram and being movable in longitudinal direction thereof, said carrier member carrying said stop pin so that the latter is movable in longitudinal direction of said bore; yieldable means carried by said support means and engaging said carrier member for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier member during reciprocation of said ram in said lower position for moving said carrier member and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably holding said carrier member and the stop pin carried thereby in said working position; and means mounted on said ram and engaging said locking means during reciprocation of said ram in said upper position for releasing said locking means so that said carrier member and said stop pin will be moved by said yieldable means from said working to said rest position.

5. A nibbling machine as set forth in claim 4, wherein said stop pin is carried by said carrier member adjustable in longitudinal direction.

6. A nibbling machine as set forth in claim 5, and including means for locking said stop pin in any adjusted position with regard to said carrier member. j

7. A nibbling machine as set forth in claim 4, wherein said engaging means is constituted by an upper transverse face of said siot in said ram.

S. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die, said ram being formed with a longitudinal slot extending in direction of movement thereof; a punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; a carrier member extending transversely through said slot in said ram and being movable in longitudinal direction thereof, said carrier member carrying said stop pin so that the latter is movable in longitudinal direction of said bore; yieldable means carried by said support means and engaging said carrier member for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; cooperating guide means on said support means and said carrier member for guiding the latter during its movement between said rest and said active position; engaging means on said ram for engaging said carrier member during reciprocation of said ram in said lower position for moving said carrier member and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably holding said carrier member and the stop pin carried thereby in said working position; and means mounted on said ram and engaging said lockingnieans during reciprocation of said ram in said upper position for releasing said locking means so that said carrier member and said stop pin will be moved by said yieldable means from said working to said rest position.

9. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a rain guided on said support means for reciprocating movement toward and away from said die, said ram being formed with a longitudinal slot extending in direction of movement thereof; a punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die' a .stop pin slidably mounted in said longitudinal bore of said punch; a carrier member extending transversely through said slot in said ram and being movable in longitudinal direction thereof, said carrier member carrying said stop pin so that the latter is movable in longitudinal direction of said bore; a pair or" plungers respectively connected to opposite ends of said carrier member and projecting therefrom in direction of movement of said ram; a pair of guide members on said support means and respectively receiving said plungers slidable in longitudinal direction thereof; yieldable means carried by said support means and engaging said carrier member for holding the latter and the stop pin in a rest position in'which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carricr member during reciprocation of said ram in said lower position for moving said carrier member andthe stop pin carried thereby against the force of said yieldable means to a working position in which the lower end'of said stop pin is located in a slot cut by theV reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasablyy holding said carrier member and the stop pin carried thereby in said working position; and means mounted on said ram and engaging said locking means during reciprocation of said ram in said upper position for releasing said locking means so that said carrier member and said stop pin will be moved by said yieldable means from said working to saidV rest position.

l0. ln a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die, said ram being formed with a longitudinal slot extending in direction of movement thereof;ra punch carried by said ram for reciprocation therewith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting theposition thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof Vthrough the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; a carrier member extending transversely through said slot in said ram and being movable in longitudinal direction thereof, said carrier member carrying said stop pin so that the latter is movable in longitudinal direction of said bore; a pair of plungers respectively connected to opposite ends of said carrier member and projecting therefrom in direction ofmovernent of said ram; a pair of guide members on said Support means, each formed with a longitudinal bore and said plungers being respectively slidably received in said longitudinal bores of said guide members; a pair of coil springs respectively engaging said plunger's, said coill springs being biased for holding said carrier member andthe stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier member during reciprocation of said ram in said lower position for moving said carrier member andtheV stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releaslable locking means carried by said support means for releasably holding said carrier member and the stoppin carried thereby in said Working position; and meansmounted on said ram and engaging said locking means during reciprocation of said ram in said -upper position for releasing said locking means so that said carrier member and said stop pin will be moved by said yieldable means from said working to said rest position.

ll. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a` die mounted on said support means; a ram guided on said support means for reciprocating movement toward and away from said die; a punch 'carried by said ram for reciprocation therewith, said punch'beingV aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch'carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and diejand a lower reciprocating positio'n in which said punch will move with a lower'c'utting end thereof through the work sheet andbeyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable in longitudinal direction of, said bore; yieldable means carried by saidsupport means and engaging said carrier means for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier means during reciprocation of said ram in said lower position for moving said carrier means and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably hoding said carrier means and the stop pin carried thereby in said working position, said releasablerlocking means including at least'one bolt member slidably guided in said support means between a retracted position and a locking position engaging said carrier means for holding the latter in said working position, and spring means cooperating with said bolt member for yieldably holding the latter in said locking position; and means mounted on said ram and cooperating with said bolt member during reciprocation of said ram in said upper position for moving said bolt member from said locking to said retracted position so that said carrier means and said stop pin will be moved by said'yieldable means' from said working to said rest position.

12. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocating movement toward and awayfrom said die; a punch carried byrsaid ram for reciprocation therewith, said punch being aligned with said dieand being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating positionin which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable in longitudinal direction ofl said bore; yieldable means carried by said support means and engaging said carrier means for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the work sheet; engaging means on said ram for engaging said carrier means during reciprocation of said ram in said lower position for moving said carrier means and the stop pin carriedthereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably holding said carrier means and the stop pin carried thereby in said working position; and cam means mounted on said ram and engaging said locking means during reciprocation of said ram in said upper position for releasing said locking means so that said carrier means and said stop pin will be moved by said yieldable means fromA said working to said rest position. Y

13. ln a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram having an upper and a lower end and being guided on said support means for reciprocating movement toward and away from said die; a punch carried on said lower end of said ram for 4reciprbcation threwith, said punch being aligned with said die and being formed with a longitudinal bore therethrough; a drive shaft mounted in said support means turnably about an axis normal to the movement of said ram, said drive shaft having an eccentric portion; an eccentric sleeve surrounding said eccentric portion of said shaft and having an inner surface slidingly engaging the outer surface of said eccentric portion; means mounted on said support means for holding said eccentric sleeve against rotation with said eccentric portion, said means being turnable about the axis of said drive shaft for adjusting the angular position of said eccentric sleeve and being arrestable with respect to said support means for holding said eccentr-ic sleeve in an angularly adjusted position; connecting means receiving said eccentric sleeve and rotatable thereabout,` said connecting means being swingably fixed to said upper en d of Asaid ram, so that by adjusting the angular position of said eccentic sleeve the position of said ram may be adjusted between an upper reciprocating position in which said punch carried by said rain will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; carrier means carrying said stop pin movable in longitudinal di- `rection of said bore; yieldable means carried by said support means and engaging said carrier means for holding the latter and the stop pin in a rest position in which the lower end of said stop pin is located above the Work sheet; engaging means on said ram for' engaging said cariier means during reciprocation of said ram in said lower position for moving said carrier means and the stop pin carried thereby against the force of said yieldable means to a working position in which the lower end of said stop pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means carried by said support means for releasably holding said carrier means and the stop pin carried thereby in said working position; and means mounted on said ram and engaging said locking means during reciprocation of said ram in said upper position for releasing said locking means so that said carrier means and said stop pin will be moved by said yieldable means from said working to said rest position.

14. A nibbling machine as set forth in claim 13, Wherein said means for adjusting the angular position of said eccentric sleeve comprise a pin member fixed to said eccentric sleeve and projecting with an end portion thereof beyond one side of the latter; a cylindrical member mounted adjacent said one side of said sleeve on said shaft turnably about the axis of the latter and being formed with a groove extending normal to the shaft axis and slidably receiving the end portion of said pin; a worm in said support means turnably about an axis normal to said shaft axis and engaging with corresponding gear teeth formed in the peripheral surface of said cylindrical member.

l5. In a nibbling machine for progressively punching slots in a work sheet, in combination, support means; a die mounted on said support means; a ram guided on said support means for reciprocation toward and away from said die, said ram being formed with a longitudinal slot extending in direction of movement thereof; a punch carried by said ram for reciprocation therewith, saidpunch being aligned with said die and being formed with a longitudinal bore therethrough; means connected to said ram for adjusting the position thereof between an upper reciprocating position in which said punch carried by said 12 ram will, during reciprocation of the latter, stay above a work sheet fed between punch and die, and a lower reciprocating position in which said punch will move with a lower cutting end thereof through the work sheet and beyond the top surface of the die; a stop pin slidably mounted in said longitudinal bore of said punch; a carrier member extending transversely through said slot in said ram and being movable in longitudinal direction thereof, said carrier member carrying said stop pin so that the latter ispmovable in longitudinal direction of said bore; a pair of plungers respectively connected to opposite ends of said Carrier member and projecting therefrom in direction of movement of said ram; a pair of guide members on said support means each formed with a longitudinal bore in which said plungers are respectively received; a pair of coil springs respectively engaging said plungers and being biased for holding said carrier member and said stop pin in a rest position in which the lower end of said stop pin is locatetd above the work sheet; engaging means on said ram for engaging said carrier member during reciprocation of said ram in said lower position for moving said carrier member and the stop pin carried thereby against the force of said coil springs to a working position in which the lower end of said stopv pin is located in a slot cut by the reciprocating punch in the work sheet slightly below the upper surface of the latter; releasable locking means including a pair of bolt members slidably guided in said support means between a retracted position and a locking position engaging with inner ends thereof said plungers for holding the carrier member in said working position, spring means cooperating with said bolts for yieldably holding the latter in said locking position, a bar extending between and fixed to the outer ends of said bolts, and a contact member fixed to said bar and having a free end projecting toward said ram; and cam means mounted on said ram and engaging said free end of said contact member during reciprocation of said ram in said upper reciprocating position for releasing said locking means so that said carrier member and said stop pin will be moved by said coil springs from said working to said rest position.

16. A nibbling machine as set forth in claim 15, wherein said cam means has an upwardly inclined surface and wherein said contact member and said cam means are adjustable in a direction transverse to the movement of said ram.

17. A nibbling machine as set forth in claim 15, and including a handle member fixed to said bar for manually releasing said locking means.

18. In a nibbling machine, in combination, support means; a die mounted on said support means; punch means having a cutting end and being mounted on said support means aligned with said die for reciprocating movement toward and away from said die, said punch means being formed with a longitudinal bore extending in direction of said movement from said cutting end into said punch means; means connected to said punch means for adjusting the position thereof between an upper reciprocating position in which said cutting end will stay, during reciprocation of said punch means, above a work sheet fed between said cutting end and said die, and a lower reciprocating position in which said cutting end will move through the work sheet and beyond the upper surface of the die so as to cut a slot in the work sheet during feeding thereof in direction transverse to the reciprocating movement of said punch means; a stop pin mounted in said longitudinal bore movable between an upper rest position in which the lower end of said stop pin is located above the work sheet and a stopping position in which said stop pin projects with the lower end thereof a short distance into a slot cut into the work sheet; spring means operatively connected at one end thereof to said support means and on the other end thereof to said stop pin and being biased so as to tend to move the latter from said stopping to said rest position; means operatively connected to said punch means and to said stop pin for moving the latter against the force of said spring means from said rest to said Stopping position during reciprocating movement of said punch means in said lower reciprocating position thereof; releasable locking means mounted on said support means and operatively connected to said stop pin for holding the latter in said stopping position during reciprocation of said punch means in said lower position thereof; and means mounted on said punch means for releasing said locking means when said punch means is moved from said lower to said upper reciprocating position so that said spring means will return said stop pin to said rest position after said locking means has been released.

References Cited by the Examiner UNITED STATES PATENTS 1,320,189 10/19' Wilson 83-916 1,650,119 11/27 Furber 83-653 1,667,184 4/28 Ballard 83-363 FOREIGN PATENTS 925,877 3/55 Germany. 884,147 8/60 Great Britain.

LEON PEAR, Primary Examiner. 

1. IN A NIBBLING MACHINE FOR PROGRESSIVELY PUNCHING SLOTS IN A WORK SHEET, IN COMBINATION; SUPPORT MEANS; A DIE MOUNTED ON SAID SUPPORT MEANS; A RAM GUIDED ON SAID SUPPORT MEANS FOR RECIPROCATING MOVEMENT TOWARD AND AWAY FROM SAID DIE; A PUNCH CARRIED BY SAID RAM FOR RECIPROCATION THEREWITH, SAID PUNCH BEING ALIGNED WITH SAID DIE AND BEING FORMED WITH A LONGITUDINAL BORE THERETHROUGH; MEANS CONNECTED TO SAID RAM FOR ADJUSTING THE POSITION THEREOF BETWEEN AN UPPER RECIPROCATING POSITION IN WHICH SAID PUNCH CARRIED BY SAID RAM WILL, DURING RECIPROCATION OF THE LATTER, STAY ABOVE A WORK SHEET FED BETWEEN PUNCH AND DIE, AND A LOWER RECIPROCATING POSITION IN WHICH SAID PUNCH WILL MOVE WITH A LOWER CUTTING END THEREOF THROUGH THE WORK SHEET AND BEYOND THE TOP SURFACE OF THE DIE; A STOP PIN SLIDABLY MOUNTED IN SAID LONGITUDINAL BORE OF SAID PUNCH; CARRIER MEANS CARRYING SAID STOP PIN MOVABLE IN LONGITUDINAL DIRECTION OF SAID BORE; YIELDABLE MEANS CARRIED BY SAID SUPPORT MEANS AND ENGAGING SAID CARRIER MEANS FOR HOLDING THE LATTER AND THE STOP PIN IN A REST POSITION IN WHICH THE LOWER END OF SAID STOP PIN IS LOCATED ABOVE THE WORK SHEET; ENGAGING MEANS ON SAID RAM FOR ENGAGING SAID CARRIER MEANS DURING RECIPROCATION OF SAID RAM IN SAID LOWER POSITION FOR MOVING SAID CARRIER MEANS AND THE STOP PIN CARRIED 